Sir Ken McCallum, the Director General of MI5, said the intelligence service had intervened operationally to disrupt a threat connected to China in the last week
A top spy chief has revealed that spooks disrupted a threat linked to China only last week as he admitted frustration at the collapse of a major spy case.
Sir Ken McCallum, the Director General of MI5, said the intelligence service had intervened operationally after a threat connected to Beijing in recent days. It is not believed to have been related to Parliament.
In his annual update on threats to national security, Sir Ken said the UK-China relationship was complex. But he added: “Do Chinese state actors present a UK national security threat? And the answer is, of course, yes they do, every day.”
He admitted he was “frustrated” by the collapse of the case against Christopher Berry and Chris Cash, two men accused of passing secrets to Beijing. They both deny the charges.
Sir Ken said it was not his role to comment on the decision by the Crown Prosecution Service (CPS) to drop the case after deeming the evidence did not show China was a threat to national security.
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But he threw his weight behind Deputy National Security Adviser Matthew Collins, who has faced criticism over the witness statements he provided to the CPS on the threat from China. He said: “I do consider him to be a man of high integrity and a professional of considerable quality.”
It came as the MI5 boss laid bare the threats to Britain’s national security in a rare public update. Sir Ken said the UK had entered a “new era” of threats, with near-record volumes of terror investigations and escalating threats from states like Russia, China and Iran.
“A more hostile world is forcing the biggest shifts in MI5’s mission since 9/11,” he said. Since 2025, MI5 and the police have disrupted 19 late-stage attack plots and intervened in hundreds of developing threats, he said.
Sir Ken said the intelligence service was confronted with a growing range of terrorist ideologies- including Islamist and extreme right wing views. Al Qaeda and Islamic State once again becoming “more ambitious, taking advantage of instability overseas to gain firmer footholds”, he said.
He said: “Terrorism breeds in squalid corners of the internet where poisonous ideologies, of whatever sort, meet volatile, often chaotic individual lives. The online environment can blur motive too. Some situations are clear-cut but it is often messier.
“In 2025, it can be hard to tell in the immediate aftermath of an appalling violent crime whether the incident is terrorist or state-directed, and thus a national security matter, or non-ideological, driven by a unique personal grievance, fixation or mental disturbance.”
MI5 are particularly concerned about how young people are being influenced by vile ideologies, and will set up a new team within the Counter Terrorism Operations Centre to help intervene earlier.
He pointed to figures that show an alarming surge in the number of young people involved in terrorism. One in five of 232 terrorism arrests last year were children under 17.
The biggest state threats to Britain stem from Russia, China and Iran. There has been a 35% increase in the number of individuals under investigation for state threat activity in the UK in the last year, with state actors increasingly using terror-style tactics, such as sabotage, arson and physical violence.
On China, he warned that it was trying to lure academic experts from the UK and intervene in public life.
Sir Ken said Russia is attempting to use online platforms sow chaos, violence and division in the UK, which has been mostly unsuccessful. After many of its spies were expelled from embassies across Europe, Moscow is now resorting to using disposable proxies.
He warned people considering helping Russia: “You’re disposable. You may well be ‘ghosted’ on payday. When you’re caught you’ll be abandoned. You won’t feature in a prisoner exchange. You’re on your own.”
MI5 has tracked more than 20 potentially lethal Iran backed plots in the last year as Iran attempts to silence its opponents around the world. “2025 has required us to grow our counter-Iran effort again,” he said.
Sir Ken also delivered a warning about the threat from AI, which he said was being exploited by state actors.
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